Development of Helical Myofiber Tracts in the Human Fetal Heart: Analysis of Myocardial Fiber Formation in the Left Ventricle From the Late Human Embryonic Period Using Diffusion Tensor Magnetic Resonance Imaging

ヒト胎児心臓の心筋線維方向を追跡 --受精後8週の心筋線維は成人と同じ配列をする--. 京都大学プレスリリース. 2020-10-09.Background: Detection of the fiber orientation pattern of the myocardium using diffusion tensor magnetic resonance imaging lags ≈12 weeks of gestational age (WGA) behind fetal myocardial remodeling with invasion by the developing coronary vasculature (8 WGA). We aimed to use diffusion tensor magnetic resonance imaging tractography to characterize the evolution of fiber architecture in the developing human heart from the later embryonic period. Methods and Results: Twenty human specimens (8–24 WGA) from the Kyoto Collection of Human Embryos and Fetuses, including specimens from the embryonic period (Carnegie stages 20–23), were used. Diffusion tensor magnetic resonance imaging data were acquired with a 7T magnetic resonance system. Fractional anisotropy and helix angle were calculated using standard definitions. In all samples, the fibers ran helically in an organized pattern in both the left and right ventricles. A smooth transmural change in helix angle values (from positive to negative) was detected in all 16 directions of the ventricles. This feature was observed in almost all small (Carnegie stage 23) and large samples. A higher fractional anisotropy value was detected at the outer side of the anterior wall and septum at Carnegie stage 20 to 22, which spread around the ventricular wall at Carnegie stage 23 and in the early fetal samples (11–12 WGA). The fractional anisotropy value of the left ventricular walls decreased in samples with ≥13 WGA, which remained low (≈0.09) in larger samples. Conclusions: From the human late embryonic period (from 8 WGA), the helix angle arrangement of the myocardium is comparable to that of the adult, indicating that the myocardial structure blueprint, organization, and integrity are already formed

Influence of low-contrast subwavelength grating shape on polarization characteristics of GaN-based light-emitting diode emissions

We analytically investigated the influence of grating shape on polarization characteristics of the emission from a GaN-based light-emitting diode with a low-contrast sub-wavelength grating (SWG), such as SiO2-SWG. The electromagnetic field distribution, calculated using the finite difference time domain method, predicted that the polarization characteristics strongly depend on the grating-side slope. A trapezoid SiO2-SWG was fabricated on the GaN-based-LED using electron beam lithography. The optical characteristics of the electroluminescence agreed with those theoretically predicted, and we succeeded in demonstrating the influence of grating shape on the polarization of LED emission

Polarized emission characteristics of UV-LED with subwavelength grating

We investigated polarized emission from a GaN-based ultraviolet light-emitting diode (UV-LED) with a subwavelength grating (SWG) on the surface. The electroluminescence (EL) spectra showed that the UV-LED exhibits high polarization selectivity, as high as s-polarization: p-polarization = 4 : 1 at a wavelength of 360 nm. The polarized EL characteristics were discussed by the theoretical consideration of Bloch modes resulting from the spatial periodicity of the refractive index in the SWG region and also by finite difference time domain calculations to explore the electromagnetic field. We succeeded in demonstrating the feasibility of a highly polarized UV-LED grown on c-plane sapphire

Propensity score-matched analysis of six-month outcomes of paclitaxel-coated balloons combined with UltraScore balloons versus conventional scoring balloons for femoropopliteal lesions

PURPOSECombination angioplasty with paclitaxel-coated balloons (PCBs) and conventional scoring balloons for femoropopliteal lesions has demonstrated satisfactory results, even for complex lesions. The UltraScore balloon (Becton Dickinson, New Jersey, USA), which has a maximum length of 300 mm, has two longitudinal 0.010-inch stainless steel wires and is a new treatment option for complex femoropopliteal lesions. However, no studies have evaluated the effect of the UltraScore balloon on femoropopliteal lesions. This study aimed to compare the clinical efficacy of angioplasty over a six-month period using UltraScore balloons versus conventional scoring balloons for the treatment of atherosclerotic femoropopliteal lesions with PCBs.METHODSA retrospective single-center observational study enrolled 272 patients who underwent PCB angioplasty combined with an UltraScore balloon (n = 58) or conventional scoring balloon (n = 214) without bailout stenting. Propensity score matching was used to minimize intergroup differences in baseline characteristics, and six-month outcomes were compared between the two groups. The primary endpoint was a technical success (i.e., residual angiographic stenosis of <30% with non-severe dissection). The secondary endpoints were the incidences of periprocedural complications, restenosis, and target lesion revascularization (TLR).RESULTSAfter propensity score matching, 50 matched pairs of patients were selected for analysis. The UltraScore group had a significantly longer vessel length (192.8 ± 94.9 versus 36.6 ± 7.9 mm, P < 0.001), a lower frequency of non-compliant balloon (26.0% versus 56.0%, P = 0.002), and a smaller PCB diameter (5.32 ± 0.65 versus 5.66 ± 0.52 mm, P = 0.002) compared with the scoring group. The primary endpoint of technical success was significantly higher in the UltraScore group than in the scoring group (76.0% versus 56.0%, P = 0.035). There were no significant differences in periprocedural complications (4.0% versus 2.0%, P = 0.562), six-month restenosis (4.0% versus 8.0%, P = 0.339), and TLR (2.0% versus 4.0%, P = 0.500) between both groups. The multivariate logistic regression analysis showed that UltraScore use was independently associated with an increase in technical success (odds ratio: 2.58; 95% confidence interval: 1.05–6.36, P = 0.040).CONCLUSIONThe use of an UltraScore balloon during PCB angioplasty for femoropopliteal lesions significantly improved technical success compared with conventional scoring balloons. UltraScore use was an independent predictor of technical success, indicating its potential advantages in peripheral intervention procedures

A cold seep triggered by a hot ridge subduction

The Chile Triple Junction, where the hot active spreading centre of the Chile Rise system subducts beneath the South American plate, offers a unique opportunity to understand the influence of the anomalous thermal regime on an otherwise cold continental margin. Integrated analysis of various geophysical and geological datasets, such as bathymetry, heat flow measured directly by thermal probes and calculated from gas hydrate distribution limits, thermal conductivities, and piston cores, have improved the knowledge about the hydrogeological system. In addition, rock dredging has evidenced the volcanism associated with ridge subduction. Here, we argue that the localized high heat flow over the toe of the accretionary prism results from fluid advection promoted by pressure-driven discharge (i.e., dewatering/discharge caused by horizontal compression of accreted sediments) as reported previously. However, by computing the new heat flow values with legacy data in the study area, we raise the assumption that these anomalous heat flow values are also promoted by the eastern flank of the currently subducting Chile Rise. Part of the rift axis is located just below the toe of the wedge, where active deformation and vigorous fluid advection are most intense, enhanced by the proximity of the young volcanic chain. Our results provide valuable information to current and future studies related to hydrothermal circulation, seismicity, volcanism, gas hydrate stability, and fluid venting in this natural laboratory

Association between hospital acquired disability and post-discharge mortality in patients after living donor liver transplantation

Background: Hospital-acquired disability (HAD) in patients who undergo living donor liver transplantation (LDLT) is expected to worsen physical functions due to inactivity during hospitalization. The aim of this study was to explore whether a decline in activities of daily living from hospital admission to discharge is associated with prognosis in LDLT patients, who once discharged from a hospital.Methods: We retrospectively examined the relationship between HAD and prognosis in 135 patients who underwent LDLT from June 2008 to June 2018, and discharged from hospital once. HAD was defined as a decline of over 5 points in the Barthel Index as an activity of daily living assessment. Additionally, LDLT patients were classified into four groups: low or high skeletal muscle index (SMI) and HAD or non-HAD. Univariate and multivariate Cox proportional hazard models were used to evaluate the association between HAD and survival.Results: HAD was identified in 47 LDLT patients (34.8%). The HAD group had a significantly higher all-cause mortality than the non-HAD group (log-rank: p < 0.001), and in the HAD/low SMI group, all-cause mortality was highest between the groups (log-rank: p < 0.001). In multivariable analysis, HAD was an independent risk factor for allcause mortality (hazard ratio [HR]: 16.54; P < 0.001) and HAD/low SMI group (HR: 16.82; P = 0.002).Conclusion: HAD was identified as an independent risk factor for all-cause mortality suggesting that it could be a key component in determining prognosis after LDLT. Future larger-scale studies are needed to consider the overall new strategy of perioperative rehabilitation, including enhancement of preoperative physiotherapy programs to improve physical function

A Kinematic Approach for Efficient and Robust Simulation of the Cardiac Beating Motion

Computer simulation techniques for cardiac beating motions potentially have many applications and a broad audience. However, most existing methods require enormous computational costs and often show unstable behavior for extreme parameter sets, which interrupts smooth simulation study and make it difficult to apply them to interactive applications. To address this issue, we present an efficient and robust framework for simulating the cardiac beating motion. The global cardiac motion is generated by the accumulation of local myocardial fiber contractions. We compute such local-to-global deformations using a kinematic approach; we divide a heart mesh model into overlapping local regions, contract them independently according to fiber orientation, and compute a global shape that satisfies contracted shapes of all local regions as much as possible. A comparison between our method and a physics-based method showed that our method can generate motion very close to that of a physics-based simulation. Our kinematic method has high controllability; the simulated ventricle-wall-contraction speed can be easily adjusted to that of a real heart by controlling local contraction timing. We demonstrate that our method achieves a highly realistic beating motion of a whole heart in real time on a consumer-level computer. Our method provides an important step to bridge a gap between cardiac simulations and interactive applications